1. Field of the Invention
This invention relate s to a spud assembly for use in a pneumatically actuated brake, clutch or other friction assembly and, in particular, to a spud assembly that reduces and/or eliminates movement of the spud and, consequently, failures at the interface between the spud and bladder within the friction assembly.
2. Disclosure of Related Art
A conventional pneumatically actuated brake, clutch, or other friction assembly includes a hub that is centered about a first axis and a holding plate that is fixed to the hub and extends radially outwardly from the first axis. The assembly further includes a pressure plate that is axially spaced from the holding plate, friction discs disposed on a first side of the pressure plate, arid a bladder disposed between the holding plate and a second side of the pressure plate. Finally, the assembly includes a spud that connects the bladder to a pump hose and through which the bladder may be selectively expanded and contracted to cause axial movement in the pressure plate and selective engagement and disengagement of the pressure plate with the friction discs. One end of the spud is connected to the bladder and the remainder of the spud extends through an aperture in the holding plate.
The above-described conventional friction assemblies have been subject to failure at the interface between the spud and the bladder because of the tendency of the spud to move during (i) installation of the pump hose; (2) loading of the pump hose; and (3) actuation and deactuation of the friction assembly. One known attempt to solve this problem has been to shape both the outer wall of the spud and the aperture in the holding plate so that each has a pair of diametrically opposed flats. The corresponding pairs of flats act to restrict rotational movement of the spud. This approach has several drawbacks, however. First, the aperture in the holding plate must be broached and/or milled thereby increasing manufacturing costs. Second, failures at the spud/bladder interface still occur. One reason for the recurring failure is that the above-described approach fails to account for axial movement of the spud relative to the bladder.
There is thus a need for a spud and spud assembly that will minimize or eliminate one or more of the above-mentioned deficiencies.